diff --git a/backend/deps.edn b/backend/deps.edn
index 623eaab86b..9fd4b90e66 100644
--- a/backend/deps.edn
+++ b/backend/deps.edn
@@ -67,13 +67,17 @@
   software.amazon.awssdk/s3 {:mvn/version "2.50.1"}
   software.amazon.awssdk/sts {:mvn/version "2.50.1"}
 
-  com.ladybugdb/lbug {:mvn/version "0.19.1"}}
+  com.ladybugdb/lbug {:mvn/version "0.19.1"}
+  ;; Required by Arrow RootAllocator (lbug only pulls arrow-memory-core).
+  org.apache.arrow/arrow-memory-netty {:mvn/version "18.2.0"}}
 
  :paths ["src" "resources" "target/classes"]
  :aliases
  {:dev
   {:jvm-opts ["--sun-misc-unsafe-memory-access=allow"
-              "--enable-native-access=ALL-UNNAMED"]
+              "--enable-native-access=ALL-UNNAMED"
+              ;; Arrow jars are on the classpath (unnamed module), not module-path.
+              "--add-opens=java.base/java.nio=ALL-UNNAMED"]
    :extra-deps
    {com.bhauman/rebel-readline {:mvn/version "0.1.11"}
     clojure-humanize/clojure-humanize {:mvn/version "0.2.2"}
diff --git a/backend/scripts/_env b/backend/scripts/_env
index 724b55f05b..5e4b02b80a 100644
--- a/backend/scripts/_env
+++ b/backend/scripts/_env
@@ -93,7 +93,8 @@ export JAVA_OPTS="\
        -XX:-OmitStackTraceInFastThrow  \
        --sun-misc-unsafe-memory-access=allow \
        --enable-preview \
-       --enable-native-access=ALL-UNNAMED";
+       --enable-native-access=ALL-UNNAMED \
+       --add-opens=java.base/java.nio=ALL-UNNAMED";
 
 function setup_minio() {
     if [ "${PENPOT_OBJECTS_STORAGE_BACKEND}" != "s3" ]; then
diff --git a/backend/scripts/run.template.sh b/backend/scripts/run.template.sh
index cff4afc870..19f47e6c0a 100644
--- a/backend/scripts/run.template.sh
+++ b/backend/scripts/run.template.sh
@@ -18,7 +18,7 @@ if [ -f ./environ ]; then
     source ./environ
 fi
 
-export JAVA_OPTS="-Djava.util.logging.manager=org.apache.logging.log4j.jul.LogManager -Dlog4j2.configurationFile=log4j2.xml -XX:-OmitStackTraceInFastThrow --sun-misc-unsafe-memory-access=allow --enable-native-access=ALL-UNNAMED --enable-preview $JVM_OPTS $JAVA_OPTS"
+export JAVA_OPTS="-Djava.util.logging.manager=org.apache.logging.log4j.jul.LogManager -Dlog4j2.configurationFile=log4j2.xml -XX:-OmitStackTraceInFastThrow --sun-misc-unsafe-memory-access=allow --enable-native-access=ALL-UNNAMED --add-opens=java.base/java.nio=ALL-UNNAMED --enable-preview $JVM_OPTS $JAVA_OPTS"
 
 ENTRYPOINT=${1:-app.main};